Stéfan Tzortzis

Yersinia pestis Orientalis in remains of ancient plague patients.

Yersinia pestis DNA was recently detected in human remains from 2 ancient plague pandemics in France and Germany. We have now sequenced Y. pestis glpD gene in such remains, showing a 93-bp deletion specific for biotype Orientalis. These data show that only Orientalis type caused the 3 plague pandemics.

Restricted diversity of dental calculus methanogens over five centuries, France.

Methanogens are acknowledged archaeal members of modern dental calculus microbiota and dental pathogen complexes. Their repertoire in ancient dental calculus is poorly known. We therefore investigated archaea in one hundred dental calculus specimens collected from individuals recovered from six archaeological sites in France dated from the 14th to 19th centuries AD. Dental calculus was demonstrated by macroscopic and cone-beam observations. In 56 calculus specimens free of PCR inhibition, PCR sequencing identified Candidatus Methanobrevibacter sp. N13 in 44.6%, Methanobrevibacter oralis in 19.6%, a new Methanomassiliicoccus luminyensis-like methanogen in 12.5%, a Candidatus Nitrososphaera evergladensis-like in one and Methanoculleus bourgensis in one specimen, respectively. One Candidatus Methanobrevibacter sp. N13 dental calculus was further documented by fluorescent in situ hybridization. The prevalence of dental calculus M. oralis was significantly lower in past populations than in modern populations (P = 0.03, Chi-square test). This investigation revealed a previously unknown repertoire of archaea found in the oral cavity of past French populations as reflected in preserved dental calculus.

Paleoproteomics of the Dental Pulp: The plague paradigm

Chemical decomposition and fragmentation may limit the detection of ancient host and microbial DNA while some proteins can be detected for extended periods of time. We applied paleoproteomics on 300-year-old dental pulp specimens recovered from 16 individuals in two archeological funeral sites in France, comprising one documented plague site and one documented plague-negative site. The dental pulp paleoproteome of the 16 teeth comprised 439 peptides representative of 30 proteins of human origin and 211 peptides representative of 27 proteins of non-human origin. Human proteins consisted of conjunctive tissue and blood proteins including IgA immunoglobulins. Four peptides were indicative of three presumable Yersinia pestis proteins detected in 3/8 dental pulp specimens from the plague-positive site but not in the eight dental pulp specimens collected in the plague-negative site. Paleoproteomics applied to the dental pulp is a new and innovative approach to screen ancient individuals for the detection of blood-borne pathogens and host inflammatory response.

Characterization of the Funeral Groups Associated with Plague Epidemics

There are several scenarios regarding how burial sites in archaeological contexts are discovered. We will focus on two scenarios according to the degree of historical knowledge regarding the studied sector. The excavation may be performed in a known funeral place or a highly suspected place (e.g., the interior or immediate exterior space in a religious monument or a parish cemetery). Also, the excavation of unexpected graves or graves discovered by chance may occur in places that had unknown or forgotten funeral purposes.

A geographic information system for the study of past epidemics: The 1705 epidemic in Martigues (Bouches-du-Rhône, France)

At the beginning of the 18th century, the Provence region was hit by several severe epidemics whose causes are still not clearly understood. To draw up epidemic profiles and to identify the pathogenic agents concerned, we constituted a large onomastic database and built a geographic information system for Martigues, a medium-sized community in the south of France. The cross-linking of epidemiological, spatial and demographical data allows us to propose a new diagnosis for the epidemic which reached Martigues in the autumn of 1705.